A vast majority of analytical instrumentation employs tubular structures for various purposes. Some of the common examples are columns for chromatographic uses, and capillaries used in capillary electrophoresis. In recent years the scientific community has advanced analytical instrumentation technology greatly by miniaturizing laboratory analyses that in the past required large instruments and lengthy procedures. One of the technologies that has accompanied these miniaturizing efforts, microfluidic technology, has brought with it a new set of challenges for the scientist. One such challenge is the ability to transfer precise aliquots of fluid materials through channels of microscale dimensions.
Examples of tubular structures used in microfluidic technology are the capillaries or pipettors used to introduce remotely stored reagents into a microfluidic device. These capillaries or pipettors may be used in high throughput devices employing microfluidic technology, which typically store the chemical reagents and sample materials used in the microfluidic device in an external storage system. Depending on the application being performed on the microfluidic device, the reagents or samples may be introduced into the microfluidic device in a continuous flow format or at frequent intervals.
The dimensions of tubular structures used in conjunction with microfluidic devices are generally quite small. The dimensions of a tubular structure often play a significant role in the usefulness of that structure for a particular application. For example, the inner diameter of a capillary used to introduce regents onto a microfluidic device determines the volume of the aliquots of materials being introduced into the device.
Similarly, the dimensions of the channels in microfluidic devices are also quite small. The dimensions of the channels also often play a significant role in the usefulness of that structure for a particular application. For example, the internal dimensions a microfluidic channel have a strong influence on the characteristics of the fluid flow through that channel.
Conventional methods of determining the internal diameter of a tube having microscale dimensions or the internal dimensions of a microfluidic channel are imprecise and time consuming. The present invention provides methods and systems for the rapid and precise measurement of the internal diameter of a microscale tube or channel.